1. Field of the Invention
The present invention relates to a touch panel, especially to a touch panel with good flatness characteristics.
2. Description of the Related Art
A touch panel is for operating various electronic devices. With reference to FIG. 8, a conventional resistive touch panel has a substrate (51), a lower conductive layer (52), an upper conductive layer (53) and a flexible printed circuit board (54).
The lower conductive layer (52) is disposed on the substrate (51) and has two opposite X-edges and two X-axis wires (521). The X-axis wires (521) are respectively formed adjacent to the two opposite X-edges and each X-axis wire (521) has a terminus (521a) extending to one of the X-edges.
The upper conductive layer (53) is adhered to the lower conductive layer (52) and has two opposite Y-edges, two opposite X-edges and two Y-axis wires (531). The X-edges of the upper conductive layer (53) correspond to the X-edges of the lower conductive layer (52). The Y-axis wires (531) are respectively formed adjacent to the Y-edges of the upper conductive layer (53) and each Y-axis wire (531) has a terminus (531a). The terminuses (531a) of the Y-axis wires (531) extend to the one of the X-edges of the upper conductive layer (53) and respectively correspond to the terminuses (521a) of the lower conductive layer (52).
The flexible printed circuit board (54) is mounted between the lower conductive layer (52) and the upper conductive layer (53) and is electrically connected to the terminuses (521a, 531a) of the X-axis wires (521) and Y-axis wires (531).
Being mounted between the lower conductive layer (52) and the upper conductive layer (53), the flexible printed circuit board (54) may cause an outer surface to be uneven. Variable thickness of the X-axis wires (521) and the Y-axis wires (531) may also cause the outer surface to be uneven and lead to frequent rejections. Therefore it is hard to maintain a high precision flatness of a touch panel.
To overcome the shortcomings, the present invention provides a touch panel with good flatness characteristics to mitigate or obviate the aforementioned problems.